1. Field of the Invention
The present invention relates to a lubricant supplying device, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
For use in image forming apparatuses such as copying machines and printers, techniques have been known that use lubricant supplying devices for supplying lubricant onto image carriers such as photosensitive drums and intermediate transfer belts. For example, refer to Japanese Patent Application Laid-open No. 2001-305907, Japanese Patent Application Laid-open No. 2007-193263, and Japanese Patent Application Laid-open No. 2010-210799.
In an example of such copying machines, non-transferred toner remaining on the photosensitive drum after a transfer process needs to be completely removed by a cleaning blade (cleaning device) making contact with the photosensitive drum. However, when abrasion occurs at the contact portion of the cleaning blade due to friction with the photosensitive drum, the non-transferred toner passes through a gap, due to abrasion, between the cleaning blade and the photosensitive drum, thereby causing a cleaning failure due to the passed-through non-transferred toner or filming (fusion) of the passed-through non-transferred toner onto the photosensitive drum.
For addressing such problems, lubricant is applied onto the photosensitive drum to reduce a friction coefficient on the photosensitive drum, thereby lessening wear and abrasion of the cleaning blade and the deterioration of the photosensitive drum. As a result, cleaning failure and filming occurring over time can be suppressed.
Specifically, in Japanese Patent Application Laid-open No. 2001-305907, a lubricant supplying device includes a brush roller (lubricant supplying roller) that slides in contact with a photosensitive drum belt (image carrier), solid lubricant making contact with the brush roller, and a compression spring urging the solid lubricant toward the brush roller in a press-contact direction. The lubricant is gradually scraped from the solid lubricant by the brush roller rotating in a certain direction. The lubricant scraped and conveyed by the brush roller is applied (supplied) on a surface of the image carrier.
In Japanese Patent Application Laid-open No. 2007-193263, a technique is disclosed that calculates consumption of lubricant from the total revolution of a photosensitive drum (image carrier). In Japanese Patent Application Laid-open No. 2010-210799, a technique is disclosed in which a drive system for a lubricant supplying roller (rotating brush) is provided independently from other drive systems.
Conventional lubricant supplying devices have problems in that supplying amounts of lubricant supplied on the image carriers change because of environmental fluctuations and because of lapse of time. If such problems occur, the supplying amounts of lubricant supplied by the lubricant supplying devices on the image carriers become insufficient, thereby causing abrasion of the cleaning blades, cleaning failures, and filming.
For solving such problems, the lubricant supplying amount may be adjusted by changing the revolution of the lubricant supplying roller when environmental fluctuations occur and over time. In this case, however, the exact product life or total consumption of the solid lubricant cannot be calculated by applying the techniques disclosed in Japanese Patent Application Laid-open No. 2007-193263 and Japanese Patent Application Laid-open No. 2010-210799. As a result, the solid lubricant having a remaining product life is replaced too early or a lubricant supplying failure occurs due to overlooking the time for replacing the solid lubricant.
Therefore, there is a need for a lubricant supplying device that can supply lubricant consistently and stably onto an image carrier without being insufficient in the supply of the lubricant on the image carrier even when environmental fluctuations occur and even over time, and that can correctly obtain a product life or total consumption of a solid lubricant, further providing a process cartridge including the lubricant supplying device, and an image forming apparatus including the process cartridge.